i am doing a swap for b18c type r in my 90 crx si... and it wont start i have a obd1 ecu and i have checked my spark which is good and the motor cranks but i am not getting fuel.. i have checked for power at the injectors and they all have 12v and when i hook them direct to the batt they do fire. this is telling me that my computer is not giving the injectors the ground signal to fire... i have checked the ecu pins A23 A24 A26 B2 d21 and d22 all have good grounds. i also have made sure my tstat is getting a ground and my batt motor and tranny all have good grounds but still nothing... anyone have any sugestions or things i may have missed or can try?

 

Your checking the wrong pins. The injector grounds are located here:
Injector 1 A1
Injector 2 A3
Injector 3 A5
Injector 4 A2

The ones you checked are the ecu grounds and logic ground wires (for shielded wiring)

 

umm kinda... they will not always be grounded as that would make the injectors always fire.... those will only be ground when the ecu sets them to ground... to make the injectors fire... thats where the injectors get the ground pulse (signal) from. injectors have a constant 12v which is provided from the main relay and then the ecu fires pulse grounds to fire the injectors at the right time... this pulse ground is what i am missing... the grounds i was checking were where the ecu is going to get its ground to use to create these pulses. and i think they are all good... i am wondering if there is some type of conditions on the injectors to fire... it obviously need to know where the crank is so it does not fire fuel at the wrong time.. but i am not getting any cel codes for any sensors the only cel i get it 20 which is for a E.L.D electric load detector for the alternator which as far as i understand will not cause a no start

 

Try checking the main relay located on the left side of the drivers side, its above the dead pedel. when you turn the car to accessory you should hear a loud click(it turning on to prime the fuel pump) then it will click off. I ended up having to replace mine after my swap. Also if you dont have jumpers make sure your dizzy is wired correctly, i was still getting spark but it wasn't firing correctly.

 

Thanks main relay and dizy are good but I just tested my power grounds and pin a23 has no ground and is at 12vdc when I turn ign on... Open wire maybe ....

 

Looking at the diagram for the power ground I looks like with ign on it would create a dead short from my main relay to ground ... So confused how this works...

 

Did you eliminate your resistor box for your injectors? Are you using OBD1 or OBD0 injectors? If you keep your obd0 injectors you need to keep the resistor box. If youre running obd1 injectors then you need to bypass the box i believe.

 

Obd2 injectors .. No resistor box ... And they are all getting power so that side is good

 

so today i pulled my entire engine wire harness and checked for continuity then put it back in and everything looks good.. the wires from the ecu to the injectors for both power and the ground signal are good...

i am using a rywire conversion harness to go from obd0 to obd1 and i am running a modded p06 ecu with a motes 2timer has anyone had problems with these....

also i noticed today that my main relay clicks with ign on some times so i pulled it down from the driver side and moving it stopped the clicking... weird right? ... anyway i checked the wires thinking there might be a lose connection but nothing so i am thinking when i moved it i shook something inside the relay and made it close... anyway it seems like its on its way out so i ordered a new one but i dont think this is my problem...

what i really would like to know is were the ecu gets its ground to use and what pin number that is on the ecu anyone with any ideas ?

 

Bump (^_^)

 

IT STARTED... so i hooked up my obd0 ecu to the car to see if it would shoot some fuel and it did so the obd1 p06 i have is no good but the car still didnt start. so i did a compression test since i have not done one since the engine rebuild and i was getting nothing... checked my work and remembered i had forgot to adjust my valves... so i went in adjusted them compression went up and THE CAR STARTED after a long winter of work.... so excited to finish it up and get it on the road... need to have a p06 expressed overnight